[Mike Harrison] is known for incredibly tiny soldering. Now he’s claiming a “world’s smallest” in the form of a stand-alone LED blinker, and we think he’s got the record.
He brought it along with him to Friday’s Beagleboard Bring-a-Hack, and we got a close look at the diminutive assembly. The project was dreamed up when [Mike] saw an announcement from Seiko about a new supercapacitor in a tiny package (likely the CPH3225A giving the blinky a footprint of 3.2 x 2.5 mm). With that in hand he added a PIC 10f322 microcontroller in a SOT23 package, an 0603 smoothing capacitor, and an SMD LED.
Blinky net to a metric ruler
US Quarter for scale (ruler is metric)
Charging jig doubles as a carrying case
With such a tiny package, the trickiest part is figuring out how to charge that supercap. [Mike] used a drill and hand files to make a square hole in a CR2032 battery holder to serve as a jig. The bottom of the supercap rests against the battery as a pogo pin makes the second connection to a terminal on the side of his assembly. It charges quickly and will happily blink away for about six minutes after charging.
Mike set out to make two of these, but dropped the second supercap when at his workbench to be forever lost in the detritus common to every electronics workshop. When he first pulled it out at the meetup we were on a rooftop terrace and we were more than a bit concerned that this would just blow away. How do you begin to fabricate such a tiny assembly? He used UV cured epoxy to glue them together first, then somehow completed the soldering by hand!
In case you haven’t heard, the best hardware conference in the world was last weekend. The Hackaday Superconference was three days of hardware hacking, soldering irons, and an epic hardware badge. Throw in two stages for talk, two workshop areas, the amazing hallwaycon and the best, most chill attendees you can imagine, and you have the ultimate hardware conference.
Already we’ve gone over the gory details of what this badge does, and now it’s time to talk about the perils of building large numbers of an electronic conference badge. This is the hardware demoscene, artisanal manufacturing, badgelife, and an exploration of exactly how far you can push a development schedule to get these badges out the door and into the hands of eager badge hackers and con attendees.
The good news is that we succeeded, and did so in time to put a completed badge in the hand of everyone who attended the conference (and we do have a few available if you didn’t make it to the con). Join me after the break to learn what it took to make it all happen and see the time lapse of the final kitting process.
Before you zip to the comments to scream “not a hack,” watch a few minutes of this teardown video. This 48 minute detailed walkthrough of a one-off art piece shows every aspect of the project: every requirement, design decision, implementation challenge, and mistake. Some notable details:
PCBs that are 1 meter wide (all one piece!)
350,000 white LEDs
Carbon fiber enclosures
1-wire serial bus (like the WS2812 only not quite) with 12 bit resolution (TLC5973)
Customized cable test jigs, PCB test jigs, and test modes
An exploration on ESD issues in production
It’s not often that one sees teardowns of professional projects like this, and there’s quite a bit to learn from in here, besides it being a beautiful piece of art. See more about the Caviar House “Emergence” project at the Heathrow Airport, along with stunning pictures and video of the display in action.
If you’re thinking about how you’d control 350,000 individual LEDs with 12 bit grayscale and have it look smooth, check out the processor requirements behind the megascroller, which only handles 98,000 LEDs. More recently, we asked how many LEDs are too many, and the answer was quite a bit lower than 350k.
It’s amazing how quickly a technological pivot will erase the existence of what was previously a modern marvel. A great example of this is the live video projection technology known as the Eidophor. In the beginning there was film, and if you shined a light through it followed by a set of lenses you could project an image for all to enjoy. But what if you didn’t want to wait for film to be developed? What if you wanted to project live video, or real-time data for a room full of people who could not be served by even the biggest of the cathode-ray tubes of the time? This question led to the development of the Eidophor whose story has been all but lost.
Mike Harrison is trying to revive the details of this amazing engineering feat and presented his findings during his talk at the Hackaday | Belgrade conference. Mike is interested in technology that is “impractical, ridiculous, absurd, or stupidly expensive” and the Eidophor certainly ticks all of those boxes. Check it out below and join us after the break where we’ll touch on the myriad challenges of developing projection technology based on hot oil and high voltage.
We have an amazing line-up of talks for Hackaday | Belgrade, Saturday April 9, in Belgrade, Serbia. The talks have been sold out for weeks. You can still get a ticket to the night’s concerts if you’re in the area. Either way, the big news this morning is that we will stream all of the talks live!
There are a ton of great speakers, check the poster below. I’m excited to hear Mike Harrison (mikeselectricstuff) speak about his journey down the rabbit hole of video projection tech, Phoenix Perry’s talk on Forward Futures, Voja Anotic’s talk about the hardware badge, Peter Philip’s talk about reinventing VHDL, and pretty much all of the rest too! From the Hackaday crew you can watch Sophi Kravitz give a talk on her shutter glass project, Chris Gammell will be talking Top Down Electronics, and I will end the 8-versus-32 argument once and for all (yeah right!).
While you’re listening to the talks, why not try your hand at badge hacking. You don’t need any hardware, you can use the emulator to try out your hacked code right now your own computer. We’ll be sending out prizes for the best entries and there are only a handful so far.
You do not want to miss these talks! If you don’t believe me, check out the talks from SuperCon last November and you’ll be convinced — Hackaday conferences provide the best collection of hardware talks anywhere.
High voltage is not something we usually tinker with at home. In fact, most of us are more comfortable working with non-lethal, low current, low voltage DC signals. When we do venture into the world of high voltage, we prefer to do it vicariously thru someone with more safety training and/or experience.
[Mike] shows us the inner workings of a 240VAC circuit breaker and explains how the different safety features in the device work. In proper MikesElectricStuff form, [Mike] finds out what it takes to destroy the device. Or in this case multiple devices, [Mike] uses his “Destruct-o-tron” to create catastrophic failure in more than one breaker. You can check out the video embedded after the break to learn a bit about how a circuit breaker works, and of course witness the carnage.
The filaments consist of 28 LEDs connected in series. The blue LEDs are covered by the typical yellow phosphors to make them glow white. It’s interesting to note that some of the filaments use a removable silicone sleeve to hold the phosphor coating, while others are coated with a resin material. The LEDs themselves are bare dies mounted to a metal strip and joined by bond wires. The entire strip can be bent, but be careful, or you’ll break the fragile bond wires.
The strips do require a fair bit of voltage to operate. The entire strip runs best at around 75 and 10~15 mA, while putting out about 1 Watt of light. [Mike] tested a strip to destruction by pumping 40 mA through it. Predictably the strip went out when the bond wires melted. The surprising part was that the strip blinked back on as the wires cooled and re-connected. The strip and wires were working as a temperature controlled switch, similar to the bimetalic strip found in old fashioned “twinkling” incandescent Christmas lights.
Not satisfied with simple tests, [Mike] went on to build a clock using the filaments as elements of a seven segment display. Inspired by numitron and minitron displays, [Mike] built a single sided PCB which held the clock circuit on the bottom and the LED filaments on top. The filaments are spaced off the board by tall wire wrap sockets, which proved to be difficult to keep from shorting out. Texas Instruments TPIC6B595 chips were used to control the LED filaments. Logically the chip functions the same as a 75LS595, which means it can be driven with a SPI bus. The open drain outputs can handle 50 volts – which makes them perfect for this application. The clock is tremendously bright, but there is still a bit of room for improvement. [Mike] notes that the phosphor of un-powered filaments tend to glow a bit due to light absorbed from nearby illuminated filaments. He’s experimenting with color filters to reduce this effect. At full power though, [Mike] says this clock would easily be daylight readable, and we don’t doubt it!
[Mike’s] final test was a bit whimsical – he built a cube entirely from the LED filaments. The cube looks awesome, but we can’t wait to see who will move things into the 4th dimension and build a tesseract!